Orkney was on patrol in Dean Castle Country Park in Kilmarnock on Tuesday, February 2, when she collapsed.
Despite the efforts of a local vet, Orkney passed away.
The 10-year-old joined Police Scotland in January 2020, serving communities across the country with the highly trained and specialised officers from the mounted branch.
Head of Specialist Operations, Operational Support Division, Superintendent Craig Smith said: “Orkney was one of a kind who was born to be a police horse. She looked after you and was a brave, kind and sweet natured mare who exceeded all expectations in her short career.
“The officers from the mounted branch are shocked and saddened by Orkney’s sudden death, and our condolences also go to her previous owner, who followed her progress with great care and attention.”